Over 7000 patients are diagnosed with pancreas cancer every year in the UK. Only 10% have it caught early enough to have surgery to cure it. The rest at best can undergo chemotherapy to extend survival, but current treatments offer at best an improvement of only a few months compared to no treatment at all. In addition only about a quarter of patients will respond to the treatment. In addition these patients often experience profound weight loss, loss of appetite and energy primarily because of the cancer process itself. Our hypothesis is that the addition of fish oil infusion to gemcitabine chemotherapy will result in an improved rate of tumour response on CT imaging.